There are a wide variety of ball bearings available today comprising fundamentally a generally annular outer race; a generally cylindrical inner race; opposed curvilinear faces on the outer and inner race defining a raceway and a plurality of ball bearings enclosed within the said raceway.
Commonly, ball bearings of the character above described are fabricated from sheet metal which has been appropriately deformed generally as disclosed in U.S. Pat. Nos. 3,317,257; 3,633,982 and 3,667,097. However, sheet metal ball bearings have been found lacking in sufficient strength necessary for many applications. Additionally, sheet metal formed bearings are relatively costly because of the large number of forming steps required.
Optionally, ball bearings of the character described may be fabricated by machining roll-stock. However, machined ball bearings are even costly than those formed from sheet metal.
It is among the objects and advantages of the present invention to provide a method for manufacturing ball bearings by employing an outer race preform fabricated of metal powder which has been appropriately molded and sintered. Such a preform is substantially less expensive to fabricate than the deforming of sheet metal and results in a ball bearing which is substantially stronger than those formed from sheet metal.
It is another object of the present invention to provide a method for manufacturing ball bearings employing the sintered metal outer race preform aforesaid including the step of deforming a portion of the preform adjacent to the raceway to entrap the ball bearings in such a fashion that the ball bearing entrapment is extremely resistant to wear and breakage.
Still another object of the present invention is to provide a method for deforming the aforesaid preform which produces a deformed radially inwardly disposed lip enclosing and entrapping the ball bearings intermediate the inner and outer race, which lip is extremely resistant to fracture due to mechanical stress.
Still yet another object of the present invention is to provide a method for manufacturing ball bearings employing in said method an annular outer race preform having an annular generally wedge-shaped flange concentrically disposed on one side face thereof which has a wall, flat from its top to its bottom, distal to and obliquely disposed to the axis of an inner race-receiving opening therein which flange is deformable radially inwardly by a tool having an annular working wall straight from side to side engagable thereto to generate a radially inwardly disposed ball bearing entrapping lip preferably having a generally flat outer face which lip, when formed in said fashion, has superior resistance to fracture under stress.